Electric switch



Aprll 26, s. LEDDICK ELECTRIC SWITCH F d Jan. 2'. 1923 Inventor- INT K yd e aim M Q m g w H Gym a 5. 5

Patented Apr. 26, 1927.

UNITED STATES 1,626,469 PATENT OFFICE.

GEORGE S. LEDDICK, OF SCI-IENECTADY, NEW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Application filed January 2, 1923.

One of the objects oi? the invention is to provide an improved electricswitch having a plurality of switch members and a common actuating meansfor the switch members, together with an interlocking arrangementbetween the switch members whereby operating the actuating means in onedirection first imparts one relative movement to the switch members andthen imparts a ditl'erent rela tive movement to the switch men'ibers.

Another object of the invention is to pro vide an improved switch havingatleast two relatively movable switch members, one for controlling onecircuit and the other for controlling another circuit, the one switchmem her being biased to the closed position but held in the openposition by the other switch member by means of an interlockingconnection which permits the one switch member to close and then reopenwhile the other switch member is being moved to the closed position, andthen closed and reopened while the other switch member is being moved tothe open position.

Another object, of the invention is to pro vide an improved latchingarrangement for holding the switch members in eiti'ier oi? a pluralityof predetermined relative positions and for limiting the speed ofoperation of the switch men'ibers. The arrangement for accomplishingthis object of my invention is claimed in a divisional application,Serial No. 740,112, tiled Sept. 26, 192i, patented May t, 1926, No.1,583.598.

These, and other objects of the invention as will be either explainedfully hereinafter or will be apparent to those skilled in the art, areattained in the electric switch which is shown on the accompanyingdrawing in which .l igure l shows a plan view of the complete switch;Fig. is a detail showing the latching arrangen'ient; Figs. 3, t and 5are simplified details showing the various relative positions of therelatively movable switch members of the switch and the interlockingarrangement: between the switch nieii'ibers; and Fig. 6 is a simplifieddiagram of a control system in which the switch of the invention is usedin the control of the lield circuit of a syncl'ironous motor.

Referring to the drawings, the electric switch comprises a switch member10 and a pair oi relatively movable switch members 11 and 11 which areinterlocked with the switch member 10 so as to control the Serial No.610,097.

operation of the switch member 10. As shown n Figs. 3, 1 and 5, theswitch member-1O is biased to the closed position; that is, inengagement with the stationary contact 12 by means of the coiled spring13 which surrounds apost 1 1- which passes through the switchmember 10and the contacttip 15 thereof. The switch member 10 and the set ofswitch members 11 and 11 are arranged to control separate circuits, andby an inspection of Fig. 6 it will be seen that the switch member 10when in the closed position connects the field wind- 111g 16 of asynchronous motor in a local circuit which includes the resistor 17 sothat the synchronous motor may be started as an induction motor untilthe speed thereof has increased to substantial synchronism. When theswitch members 11 and 11 are closed and the switch member 10 opened, thefield winding of the synchronous motor is connected to the directcurrent supply circuit 18 so that the speed of the motor will be broughtinto synchronism with the alternating supply circuit 19 and the motorwill operate as asynchronous motor. This is only one of the uses of myinvention, and I can conceive that the invention may be applied to otheruses in which it is desirable that the sequence of operation of aplurality of relatively movable switch members shall proceed in adefinite order.

' The switch members 11 and 11 are mounted upon the shaft :20 which ismounted in the bearings 21 and 22, so that these switch members arepivotally supported for movement to and from their respective stationaryswitch contacts 23 and 24. By reference to Figs. 3, 4i. and 5, it willbe noted that there is an interlocking connect-ion between the switchmember 11 and the switch member 10 so that the switch member 10 iscontrolled in its movement by the switch member 11. In Fig. 4 the twoswitch memhers are shown in their relative positions when both switchmembers are in their respective open position. It will be seen that thebent strip 2:), which is secured to the shaft 20 and also to the switchmember 11, is in. effect an extension of the switch member 11 and servesas a cam interlock ing connection between the switch members 11 and 10.\Vith the switch member 11 in the full open position, the upper end ofthe switch member 10 is engaged by the extension 25 at the apex 26 otthe angle so that the switch member it) is held in the open positionagainst the bias ot the sprin 13 which tends to close the same. ll henthe switch member 11 is moved clockwise about its pivotal supports alimited distance as shown in Fig. 5. the upper end of the switch member10 is permitted to move counter-clocltwise by reason of the action ofthe spring 13 so that the switch contact 15 will make engaggem at withthe stationary contact 12 and connect the syiuchroimus motor lield in alocal circuit including the resistor 17 (Figs. 5 and (3). i theClUClUYlSQ movement of the switch 11 mber 11 is continued, the upper endof the extension will engage the upper end ot the switch member 10 andwill move the switch member 10 to the open position against. the actionof the spring 13 until this opening movement is arrested by the stop QT.The switch member ll will make engagement with its stationary contact 23as shown in Fig. 3, thereby connecting the field oi the synchronousmotor to the said direct current source of supply 18. It will beobserved from the foregoing: description that a continuous movement ofthe switch member 11 imparts one relative movement to the switch membersand then imparts a different relative movement; that is, movinn theswitch member 11 toward the closed position first permits the switchmember 10 to move to t lie closed position and then opens the switchmember 10 before the switch member 11 is moved to the closed position.It will also be observed that in openine the switch, a continuousmovement of the switch member 11 in the opening direction first impartsone relative movement to the switch members and then a differentrelative movement: that is, in moving the switch member 11. from theclosed position as shown in Fig. 3 towards the full open position asshown in Fig. l. at an intermediate position the switch member 10 willbe permitted to close as shown in Fig. and will be again returned to theopen position when the switch member 11 has reached the full openposition as shown in Fig. i. This has an advantage in that. for example.when the switch is used for controlling the field ot a synchronous motorLil as shown in Fig. (i, when the motor iield is disconnected from thesupply circuit it is connected. in a local circuit so as to reduce thecurrent in the field circuit preparatory to finally opening the motorfield circuit.

For certain applications as, for example, in the control of the holdcircuit of a syn chronous motor as shown in 6, it is desirable that thespeed (it operation oi the switch members be limited. and for thatpurpose I have provided the latching arrangement shown in Figs. 1 and 2which I shall now describe. I would have it understood that thislatching arrangement is not limited in its application to the particulararrangement oi relatively movable switch members which 1 have previouslydescribed, but that this feature of my invention is applicable generallywhere it is desired to limit the speed ot operation of a plurality oiswitch members which are actuated by a common actuating means.

Referring to Figs. 1 and 2, the handle which is connected with the shaftprovides a common actuating means tor the switch members previouslydescribed. A latching arrangement is provided whereby this handle isheld in either one of a plurality of predetermined positions and thespeed ctoperation of this handle is limited. The spring pressed dctentprovides a locking member which is carried by and movable with thehandle 28 and this detent cooperates with the stationary dial plate 230,which may be mounted on the casing of the switch. for holding the handle28 in either one of a plurality oti predetermined positions and forlimiting the speed of operation of the handle. in the upper end of thehandle there is provided an operating member for the detent 2t).'lhismember takes the form of a resiliently mounted push button #31which normally biased out of eugagementv with the dial plate I by meansof the spring :32, but when this button depressed shown in Fig. l. thelc'tt-haml end thereot engages the resilient detent 2S) and moves thesame out of cnga ctement with the notched upper edge of the dial platePa").

The operation of this part oi my invention is as follows: In Fig. 2 thehandle (it the switch shown as in the running position. In order to movethe handle to the open position it is necessary to iii-st press thebutton Ell so as to release the detent 2*.) cment. with the notch in theupper edge oi the dial plate 30. The. handle may then be movedcouiiter-clrurlcwise until the left-hand edge of the detent 725') slidesunder the portion :3 ot the dial plate 230. burther movement of thehandle in the counterclockwise direction is arrested because of the factthat. the pin oi the push button ii is arrested at the lett-hand end oithe slot in the dial plate so. so that the push button must be releasedto permit the handle to be moved until the detent 29 drops into thenotch ill and further movement oi the bandle in this direction isarrested. The relative positions of the itch members will now he asshown in rig. in order to continue the :ounter-clocltwise movement oithe handle. it will be necessary to press the push button so as tothereby permit the detent 29 to slide under the portion 3:) of the dialplate, and by moving the handle a short distance counter-clockwise, thedetent will be engaged under the portion 35. However, further movementof the handle is arrested until the push button 31 is released becauseof the fact that the end. of the pin connected with the push button willengage the left-hand edge of the slot 36. hen the push button has beenreleased, the bandle may be moved a short distance counterclockwiseuntil the detent 29 drops into the notch 37 Further movement of thehandle counter-clockwise is thereby prevented. The relative positions ofthe switch members will now be as shown in Fig. 4..

In order to close the switch member 11, it will be necessary to pressthe push button 31, move the handle 28 a short distance clockwise untilthe pin associated with the push button 31 engages with the right-handedge oi the slot 38, then release the push button out of engagement withthe slot- 38 so that the handle may be moved to the middle operativ'eposition at which the detent 29 will arrest further movement. In orderto move from the middle position to the final position, that shown inFig. 2, it will be necessary to again press the push button. 31, movethe handle 28 a short distance clockwise until the detent 29 engagesunder the portion 33 of the dial plate, then release the push button andfinally move the handle to the position shown in Fig. 2.

it will be observed that a definite sequence oi. operations must be hadin order to move the handle from one definite position to anotherdefinite position, and that this sequence oi operations will limit thepermissible speed of operation of the handle so as to thereby preventthe handle from being thrown directly from one extreme position to theother. It will also be observed that the latching arrangement serves topositively hold the handle in either one oi the predetermined definitepositions of the handle so that there is no possibility oi unintentionaloperation of the switch members. The above described latchingarrangen'ient of Figs. 1 and 2 is claimed in my said divisionalapplication on which my said. Patent- No. 1,583,598 issued on May 4.1926.

In accordance with the provisions of the patent statutes, I havedescribed the prin ciple of operation of my invention, together with theapparatus which I now consider to represent the best eml'iodimentthereo'i, but l. desire to have it understood that the apparatus shownis only illustrative and that the invention can be carried out by othermeans.

What I claim new and desire to secure by Letters Patent of the UnitedStates, is

l. The combination in. an electric switch of two relatively movableswitch members, means for biasing the first ot the switch members to theclosed position, a pivotal support for the second switch member, and acam connected with the second switch member for holding the first switchmember in the open position, releasing the same to close when the secondswitch member is moved toward a prcdetern'iined position, and thenopening the first switch member before the second switch member reachesthe said predetern'iined position.

2. The combination in an electric switch of two relatively movableswitch members, means for biasing the first of the switch members to theclosed position. and a pivotal support for the second of the switchmembers, the second of said switch members having an extension whichengages the first switch member for holding the first switch member inthe open position while the sec- 0nd switch member is in the openposition, for releasing the first switch member to close when the secondswitch member is moved about the said pivotal support toward the closedposition and for opening the first switch member prior to the closing ofthe second switch member.

3. The combination in an electric switch of two relatively movableswitch members, a pivotal support for the first of said switch members,and connections whereby the of said switch members while in the openposition holds the second switch member in the open position against thebias or the stone to the closed position, moving the first switch membertoward the closed position first releases the second switch member tomove to the closed position in accordance with its bias and then opensthe second switch member before the movement of the hrst switch memberto the closed position is completed.

4;. The combination in an electric switch of two relatively movableswitch members, means for biasing the first of the switch members to theclosedv position, a common actuating insane for the switch members, andinterlocking connections between the switch members whereby the first ofsaid switch members is held in the open position against its bias by thesecond of said switch members. moving the second switch member towardthe closed position first releases the first switch member to move tothe closed position, and the first switch member is re turned to theopen position. by a continuation of the movement of the second switchmember to the closed position.

In witness whereof, I have hereunto set my hand this 29th day ofDecember, 1922.

GEORGE S. LEDDICK.

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